The present disclosure relates to an image forming apparatus configured to detect a deviation of AC voltage supplied from a commercial power supply.
The image forming apparatus is supplied with power from a commercial power supply (AC power supply) via an outlet and a power cable. The commercial power supply is connected to a power supply device of the image forming apparatus. The power supply device includes a rectifying circuit and a power conversion circuit (a switching power supply circuit, a converter, or the like) for generating voltages suitable for circuits or elements included in the image forming apparatus. Here, the voltage of the commercial power supply may be deviated from the nominal voltage. When the deviation is large, the power supply device inside the image forming apparatus may be broken down.
There is known an example of technique as below, in which an abnormality of voltage of the commercial power supply (AC power supply) is detected so as to protect a circuit or an element included in the power supply device. Specifically, there is a power supply device, which converts a power input from the power supply into a first power to be output, detects a voltage of the power from the power supply, generates a power supply voltage detection signal indicating a detection voltage value, determines whether or not the detection voltage value is within a first permissible range, outputs a first control signal when determining that the detection voltage value is not within the first permissible range, outputs predetermined information when the first control signal is output, determines whether or not the detection voltage value is within a second permissible range that includes the first permissible range and is wider than the first permissible range, outputs a second control signal when determining that the detection voltage value is not within the second permissible range, and stops operations of a part of elements constituting the power supply device, a part estimated to be damaged when the voltage of power from the power supply is deviated, or the entire thereof when the second control signal is output. When an abnormality of the commercial power supply occurs, the power supply device included in the apparatus is protected.
Quality of the commercial power supply (electric power circumstance) depends on a country or a region. There are countries or regions where an amplitude and a frequency of the commercial power supply are always stable to have a regular waveform, while there are countries or regions having a large deviation of amplitude (deviation from nominal voltage or a voltage deviation) and a large deviation of a frequency. In a country or a region where the infrastructure related to electric power is not sufficiently developed, the voltage of the commercial power supply is apt to deviate from the nominal voltage. In addition, there is a tendency that the in-house wiring has many mistakes in the region where the voltage of the commercial power supply is apt to deviate. A mistake in wiring may cause the situation where an AC voltage deviated largely from the nominal voltage is supplied to the image forming apparatus.
When an absolute value of a peak value of the voltage from the commercial power supply exceeds a value and a period of design that the power supply device of the image forming apparatus can endure, an element or a circuit (e.g., a switching element) included in the power supply device is broken down. For this reason, it is necessary to design the power supply device of the image forming apparatus to endure as much as possible even if a deviation of the commercial power supply from the nominal voltage becomes large so that the absolute value of the peak value of the AC voltage becomes large in a country or a region where the image forming apparatus is sold and used.
On the other hand, when the absolute value of the peak value of the voltage from the commercial power supply is decreased or the decreased state is continued, the image forming apparatus may stop its operation because of a decrease of voltage supplied to the circuit. For this reason, it is preferred to design the power supply device of the image forming apparatus so that the image forming apparatus continues to operate even if the AC absolute value of the peak value of the voltage from the commercial power supply continues for a certain period in a country or a region where the image forming apparatus is sold and used.
However, there is a problem that it is difficult to know a situation of the voltage deviation from the nominal voltage in a country or a region where the image forming apparatus is sold and used. When the deviation of the AC voltage of the commercial power supply from the nominal voltage, a period from start to end of the exceeding the permissible range, occurrence frequency of the deviation, and the like in the country or the region are not known, it is difficult to design and develop the power supply device suitable for the country or the region. In other words, it is not possible to define a specific specification (e.g., a withstand voltage) of the power supply device in which the power supply device is not broken down so that the image forming apparatus can continue to operate when a voltage deviation of the commercial power supply from the nominal voltage occurs. In addition, it is also difficult to determine whether or not the current power supply device of the image forming apparatus has a problem or should be improved.
Here, the known power supply device described above detects abnormality of the power supply voltage so as to protect the power supply device and issues warning before the protecting function works. However, information indicating a situation of the commercial power supply in a country or a region where the apparatus is used is not saved. Accordingly, it is not possible to know a situation of a voltage deviation of the commercial power supply in a country or a region where the image forming apparatus is sold and used.